<template>
	<el-menu
		:default-active="activeMenu"
		mode="horizontal"
		@select="handleSelect"
	>
		<template v-for="(item, index) in topMenus">
			<el-menu-item
				v-if="index < visibleNumber"
				:key="index"
				:style="{'--theme': theme}"
				:index="item.path"
			>{{ item.meta.title }}</el-menu-item>
		</template>

		<!-- 顶部菜单超出数量折叠 -->
		<el-submenu v-if="topMenus.length > visibleNumber" :style="{'--theme': theme}" index="more">
			<template slot="title">更多菜单</template>
			<template v-for="(item, index) in topMenus">
				<el-menu-item
					v-if="index >= visibleNumber"
					:key="index"
					:index="item.path"
				>{{ item.meta.title }}</el-menu-item>
			</template>
		</el-submenu>
	</el-menu>
</template>

<script>
    import { constantRoutes } from '@/router';

    // 隐藏侧边栏路由
    const hideList = ['/index', '/user/profile'];

    export default {
        data() {
            return {
                // 顶部栏初始数
                visibleNumber: 5,
                // 当前激活菜单的 index
                currentIndex: undefined
            };
        },
        computed: {
            theme() {
                return this.$store.state.settings.theme;
            },
            // 顶部显示菜单
            topMenus() {
                const topMenus = [];
                this.routers.map((menu) => {
                    if (menu.hidden !== true) {
                        // 兼容顶部栏一级菜单内部跳转
                        if (menu.path === '/') {
                            topMenus.push(menu.children[0]);
                        } else {
                            topMenus.push(menu);
                        }
                    }
                });
                return topMenus;
            },
            // 所有的路由信息
            routers() {
                return this.$store.state.permission.topbarRouters;
            },
            // 设置子路由
            childrenMenus() {
                var childrenMenus = [];
                this.routers.map((router) => {
                    for (var item in router.children) {
                        if (router.children[item].parentPath === undefined) {
                            if (router.path === '/') {
                                router.children[item].path = '/' + router.children[item].path;
                            } else {
                                if (!this.ishttp(router.children[item].path)) {
                                    router.children[item].path = router.path + '/' + router.children[item].path;
                                }
                            }
                            router.children[item].parentPath = router.path;
                        }
                        childrenMenus.push(router.children[item]);
                    }
                });
                return constantRoutes.concat(childrenMenus);
            },
            // 默认激活的菜单
            activeMenu() {
                const path = this.$route.path;
                let activePath = path;
                if (path !== undefined && path.lastIndexOf('/') > 0 && hideList.indexOf(path) === -1) {
                    const tmpPath = path.substring(1, path.length);
                    activePath = '/' + tmpPath.substring(0, tmpPath.indexOf('/'));
                    this.$store.dispatch('app/toggleSideBarHide', false);
                } else if (!this.$route.children) {
                    activePath = path;
                    this.$store.dispatch('app/toggleSideBarHide', true);
                }
                this.activeRoutes(activePath);
                return activePath;
            }
        },
        beforeMount() {
            window.addEventListener('resize', this.setVisibleNumber);
        },
        beforeDestroy() {
            window.removeEventListener('resize', this.setVisibleNumber);
        },
        mounted() {
            this.setVisibleNumber();
        },
        methods: {
            // 根据宽度计算设置显示栏数
            setVisibleNumber() {
                const width = document.body.getBoundingClientRect().width / 3;
                this.visibleNumber = parseInt(width / 85);
            },
            // 菜单选择事件
            handleSelect(key, keyPath) {
                this.currentIndex = key;
                const route = this.routers.find(item => item.path === key);
                if (this.ishttp(key)) {
                    // http(s):// 路径新窗口打开
                    window.open(key, '_blank');
                } else if (!route || !route.children) {
                    // 没有子路由路径内部打开
                    this.$router.push({ path: key });
                    this.$store.dispatch('app/toggleSideBarHide', true);
                } else {
                    // 显示左侧联动菜单
                    this.activeRoutes(key);
                    this.$store.dispatch('app/toggleSideBarHide', false);
                }
            },
            // 当前激活的路由
            activeRoutes(key) {
                var routes = [];
                if (this.childrenMenus && this.childrenMenus.length > 0) {
                    this.childrenMenus.map((item) => {
                        if (key === item.parentPath || (key === 'index' && item.path === '')) {
                            routes.push(item);
                        }
                    });
                }
                if (routes.length > 0) {
                    this.$store.commit('SET_SIDEBAR_ROUTERS', routes);
                }
            },
            ishttp(url) {
                return url.indexOf('http://') !== -1 || url.indexOf('https://') !== -1;
            }
        }
    };
</script>

<style lang="scss">
.topmenu-container.el-menu--horizontal > .el-menu-item {
  float: left;
  height: 50px !important;
  line-height: 50px !important;
  color: #999093 !important;
  padding: 0 5px !important;
  margin: 0 10px !important;
}

.topmenu-container.el-menu--horizontal > .el-menu-item.is-active, .el-menu--horizontal > .el-submenu.is-active .el-submenu__title {
  border-bottom: 2px solid #{'var(--theme)'} !important;
  color: #303133;
}

/* submenu item */
.topmenu-container.el-menu--horizontal > .el-submenu .el-submenu__title {
  float: left;
  height: 50px !important;
  line-height: 50px !important;
  color: #999093 !important;
  padding: 0 5px !important;
  margin: 0 10px !important;
}
</style>
